In UMTS (Universal Mobile Telecommunications System), which is also referred to as “W-CDMA (Wideband Code Division Multiple Access),” code division multiple access (CDMA) is used as a radio access scheme. CDMA is a radio access scheme that does not provide orthogonality within cells. Consequently, in UMTS, transmission power control (TPC) is executed in order to reduce the multiple access interference (interference between users within cells, interference within cells, etc.) that accompanies the near-far problem.
Also, in the uplink in LTE (Long Term Evolution), single carrier frequency division multiple access (SC-FDMA) is used as a radio access scheme (see, for example, non-patent literature 1). SC-FDMA is a radio access scheme that provides orthogonality within cells. Also, in LTE, link adaptation is carried out, such as scheduling per transmission time interval (TTI) that is one msec long, adaptive modulation and coding (AMC) and so on. Consequently, in LTE, unlike W-CDMA, it is not necessary to execute transmission power control for reducing the interference between users within cells.
Meanwhile, since LTE is based upon one-cell frequency reuse, interference from nearby cells (inter-cell interference) and the propagation loss (path loss) between user terminals and radio base stations increase. Consequently, in LTE, transmission power control to take into account inter-cell interference, propagation loss and so on is executed in order to fulfill the required received quality with respect to uplink signals (see, for example, non-patent literature 1).